The Dilute Magnetic Properties of Monolayer MoS<sub>2</sub> Doped with Transition Metal Fe and VA Atoms

Abstract

The two-dimensional material MoS2 has attracted a growing attention due to its potential applications in electronic devices in recent years [1,2,3], and the monolayer MoS2 is a direct gap semiconductor with a band gap of 1.8eV [4]. In the existing studies, it has indicated that MoS2 can get an available magnetism with doping transition metal atoms [5], and is expected to be a new generation of diluted magnetic semiconductor (DMS) [6,7]. Moreover, we found that Fe-doped MoS2 could present a strong magnetism but a semimetal characteristic, losing its original semiconductor properties while obtaining magnetism. Therefore, it is necessary to explore some methods to make monolayer MoS2 exhibit both magnetic and semiconductor properties. In this paper, we propose the method of N, Fe atoms co-doping to achieve this objective. The structural, electronic and magnetic properties of MoS2 doped with transition metal Fe and VA atoms have been investigated by first principle calculations based on density functional theory. The 3×3×1 supercell of monolayer MoS2 as a calculation model has been used. The result shows that pure MoS2 has no magnetism, while Fe-doped MoS2 exhibits a good magnetism about 1.849μB but a semimetal characteristic. This is due to that Mo-4d, S-2p, Fe-3d states has a strong coupling around the Femi energy for the introduction of Fe atom, and the Femi energy only pass through the spin-up density of states. For the co-doping with VA atoms and Fe atoms, it is found that the magnetic moment of Fe-N, Fe-P and Fe-As co-doped MoS2 is 0.956μB, 0.775μB, 0.782μB. Moreover, the Fe-N co-doped MoS2 presents semiconductor characteristics, in contrast, Fe-P and Fe-As co-doped MoS2 appear semimetal properties. It indicates that the semimetal characteristic of Fe-doped MoS2 could change into indirect band gap semiconductor due to the introduction of N atom. The band gap is 0.2eV. Our study demonstrate that the method of Fe, N co-doping could make MoS2 have good magnetic and also semiconductor properties at the same time.